Advice on HP Procurve fiber switch

Have you considered Trunks between the perimeter switches and the core switches?  You can also use LACP to create very large connections between the different switches which would alleviate single ports carrying all of the traffic between switches.  If you have servers that have high bandwidth, and they only have 1 NIC, you could put in multiple NICs and team them to a switch as well.  You may not need to purchase, just optimize.